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Abrupt intensification of North Atlantic Deep Water formation at the Nordic Seas during the late Pliocene climate transition
Author(s) -
Sato Masahiko,
Makio Masato,
Hayashi Tatsuya,
Ohno Masao
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl063307
Subject(s) - north atlantic deep water , geology , oceanography , interglacial , quaternary , coercivity , climatology , geophysics , paleontology , deep water , physics , condensed matter physics
Knowledge of the evolution of North Atlantic Deep Water (NADW) is key to understanding the past evolution of the climatic system. Here we developed a new rock‐magnetic method to determine the constituent magnetic minerals of sediments and report on the evolution of NADW during 2.2–2.9 Ma. We measured isothermal remanence acquisition curves of North Atlantic deep‐sea sediments drilled at the Gardar Drift and decomposed the first derivatives of these curves into high‐coercivity and low‐coercivity components. Residuals of the decomposition were sufficiently small throughout the study interval, confirming that the Gardar Drift sediments represent a mixing of the two end‐members. Fractional changes of the high‐coercivity component represent variation of the Iceland‐Scotland Overflow Water, a branch of NADW formed at the Nordic Seas. The high‐coercivity component increased significantly during an interglacial period just after ~2.68 Ma, which suggests that NADW formation in the Nordic Seas abruptly intensified at this time.